1. Field of the Invention
This invention relates power supply fans, and more particularly to providing control and power for power supply fans.
2. Description of the Related Art
As electronic devices, such as microprocessors, central processing units (CPUs), servers, and other similar types of electronic components become faster and are reduced in size, power consumed within the system per unit volume (power density) increases dramatically. Therefore, it is essential to dissipate the heat generated by electronic components within the system during its operation to keep the electronic components within their normal operating temperature ranges. If the electronic components operate outside of their operating temperature ranges, the life span of the electronic components will be reduced or fail immediately.
One effective technique for dissipating the heat from electronic components, such as a power supply, is to provide an internal fan, or fan assembly, to directly apply a relatively high-velocity air stream across the surface of the electronic components. By forcing high-velocity air across the surface of the internal component(s), the conductive heat transfer coefficient for the surface of the internal electronic components is increased, thus increasing the convection cooling.
Current technology for power supplies has the power supply providing power internally for the internal or attached fans. Power supplies can fail if the cooling fan fails, leading to overheating of electronic components, or the electronic components can fail themselves. If the power supply fails, it follows that the power supply fan shuts off since there will not be any power supplied to sustain operation of the fan.
In many systems today, such as server systems, power is supplied to internal components from alternate sources besides the power supply. Moreover, in these systems, the power supply fans may be used to cool other components besides the power supply itself. When a power supply fan fails due to the power supply failing, the internal system""s components may reach an over temperature situation. In the over temperature situation, components can be exposed to harm due to exceeding the operating temperature range. Further, if the system uses other fans, these fans may need to increase their speed in order to makeup for the loss of the power supply fan. In this case, acoustical noise is increased due to the higher fan speed of the system fans.